Engine starter



Patented Aug. 14, 195i UNITED STATES PATENT OFFICE ENGINE STARTERRaymond H. Foster, Hasbrouck Heights, and

Clinton H. Havill, South Orange, N. .L, assignors to Bendix AviationCorporation, Teterboro, N. J., a corporation of Delaware Application May15, 1946, Serial No. 669,91!

'=7 Claims. 1

This invention relates to engine starters, and particularly toimprovements in a starter clutch jaw member and elements associatedtherewith.

A starter of one type to which the invention applies, comprises anaxially stationary nut rotatably driven through the intermediary of adry or wet disc clutch, and a screw shaft in the nut splined to astarter clutch jaw member for cooperation with a clutch element on anengine shaft.

The starter clutch member is frictionally held so that, when the nutrotates, it first moves the screw shaft longitudinally from an initialposition, which likewise moves the clutch member, through theintermediary of a spring and a meshing rod, into engagement with theengine clutch element, whereupon the latter is rotated to normally startthe engine.

The end of the starter casing, at which its clutch member is disposed,is disposed within one end of the engine crank case, which presents theproblem of sealing the starter casing against the ingress of the engineoil to the aforesaid disc clutch and other parts.

- Also, the starter is subjected to the vibration of the engine which,unless counteracted, as by the present invention, has adverse affects onparts of the starter, such as the oil sealing means.

In starters of the above-indicated type heretofore employed, the meshingrod is subject to break-age, because it is too small in diameter, andcauses oil leakage, between the starter clutch member or jaw and themeshing rod, through a sliding seal. Such leakage is very undesirable,since any oil reaching the disc clutch causes the clutch torque settingto be reduced, so that the starter cannot start the engine.

It is undesirable to have screw threads or other sharp edges on certainparts of thedriving jaw itself, which must be free from such weakeninginfluence, so that a mounting for the jaw on the rod, or a seal toprevent the aforesaid leakage, should be provided without such threadsor edges.

The jaw should be prevented from displacement by reason of its positionor other causes such as vibration, and any means for holding the jawagainst such displacement should be directly accessible from theexterior of the starter, so that the jaw may be readily assembled andreplaced.

Among the objects of the invention are to overcome the above-mentionedundesirable features and to provide the advantages mentioned, and to doso in an effective manner by novel'and improved means.

Another object is to provide a fixed or permanent seal, between adriving clutch member and a meshing rod, which may be efieoted withoutscrew threads or similar weakening sharp edges on the clutch member.

Another object is to provide the above-mentioned seal in combinationwith jaw retaining means which is directly accessible from the exteriorof the starter or like structure for the removal of the jaw.

Another object is to provide novel means whereby, as in a starter formounting on an engine having high amplitude of vibration, the meshingrod and other parts are prevented from adversely affecting the oil orfluid seal and, as where the engine is of low amplitude of vibration,the meshing rod may be of. large diameter and hollow to enclose theSpring means through which the screw shaft advances the starter jaw.

Another object is to provide means whereby the starter clutch jaw hasautomatic radial centering movement relative to the engine clutch jawelement.

Another object is to provide means whereby a nut or the like, forholding the starter clutch jaw on the meshing rod, may be turned homeand removed without the aid of a separate tool' for holding the jaw.

A further object is to provide improved means of the above-indicatedcharacter that are simple and durable in construction, economical tomanufacture and effective in operation.

These and other objects and features of the invention are pointed out inth following description in terms of the embodiment thereof which isshown in the accompanying drawing. It is to be understood, however, thatthe drawing is for the purpose of illustration only, and is not designedas a definition of the limits of the invention, reference being had tothe appended claims for this purpose.

In the drawing:

Figure 1 is a, side view, partially in section and partially inelevation, of a portion of a starter structure embodying the inventionin one form;

Figure 2 is a detail sectional View, taken substantially along the line2-2 of Figure 1.

Figure 3 is view similar to a portion of Figure 1, showing the inventionin modified form,

Figure 4 is an enlarged detail'of parts shown in Figure 3, in positionprior to being placed in the position thereof in Figure 3; and

Figure 5 is a view taken substantially along the line 5-5 of Figure 3.

In Figure 1, which shows only a portion of a starter sufficient for anunderstanding of the invention, the structure comprises, in general, aninner starter casing portion I8 secured, at one end, to an engine crankcase l2, as by studs l4, and, at the other end, to another startercasing portion l6, as by screws l8. A casing member 28, secured, as bythe studs l4 between the casing portion I8 and the crank case [2, and tothe portion l8, as by screws H, has a shoulder 22, which retains aflange 24 of a rotatable barrel 26 relative to the casing portion [8.

An end wall 28, of the barrel 26, supports planet gears 38 operatingbetween an orbital gear 32, fixed to the casing portion 18, and a sungear 34, on a shaft 36, which sun gear is driven in a usual manner by amotor through further speed reducing means. A spline nut 38 is connectedto the barrel 26 therein by a torque-limiting disc pack 48 havinginterlayered discs fixed to the nut and the barrel, respectively, andaxially biased together by springs 42 held in adjusted relation to thediscs, as by a ring nut 44 screw threaded in the opposite end of thebarrel 26. A ring member 35, carrying centering projections 61 for thesprings 42, acts, in the retracted position of the member 52illustrated, as a bearing for the latter, but has a chamfer 4| whichcooperates with a chamfer 39 on the member 52, in the extended positionof the latter, to permit a certain amount of radial movement of themember 52 for automatic centering relative to the engine jaw element 54.

A screw shaft 46, having long-lead thread connection to the spline nut38 therein, surrounds a hollow bearing sleeve 48 for the shaft 36, andhas an axially slidable spline connection 58 to a starter clutch jawmember 52, which is adapted to engage a cooperating engine clutch jawelement 54 on an engine shaft 56. The starter clutch jaw member 52 isadapted to rotate, and move axially toward the engine element 54, in anoil seal and friction device 55 mounted on the member 28. The long leadthread connection between the screw shaft 46 and the spline nut 38 andthe spline connection 58 are loosely fitted to permit limited radialplay between the screw shaft 46 and spline nut 38 and between the screwshaft 46 and the member 52. The radial play between the respective partspermits the radial movement of the member 52 as previously described.

The member 52 has an axially apertured hub or Web portion 58 throughwhich extends a reduced diameter shank portion 68 of a meshing rodmember 62, which further comprises a portion 64 of larger diameterhaving a radially outwardly projecting flange 66 axially behind aninwardly projecting flange 68 on the screw shaft 46.

A groove 18, in the portion 64 facing the hub 58 of the starter jaw 52,is adapted to receive a doughnut gasket or seal 12 for compression inthe groove, through the intermediary of the hub, by holding means, suchas a nut (4 locked in position on the shank 68. The nut 14 and theflange 66 cooperate to normally hold the clutch member 52 againstcomplete separation from the starter.

The meshing rod 62, in this instance, is constructed to be relativelyshort in length whereby to reduce its mass and the inertia of theassembly including the rod and the jaw member 52 as to radial vibration,the assembly thereby being a better radially balanced unit againstangular deflection relative to its axis. 7

A substantial clearance 13 is provided between the flange 66 of themeshing rod and the screw shaft 46, and a similar clearance 15 isprovided 4 between the portion 64 of the meshing rod and the screwshaft, whereby the jaw member 52 may automatically adjust itselfradially when engaged to the engine jaw element 54, and whereby thetransmission of vibration from the screw shaft 46 to the clutch jawthrough the meshing rod 62 is prevented or reduced.

The screw shaft 46 is limited in its right hand axial movement, asviewed in the drawing, by engagement with an end flange 16 on thebearing sleeve 48, and, in its left hand axial movement, by engagementof a shoulder 18 on the shaft with a shoulder 88 on the spline nut 38.

As better seen in Figure 2, the mesh rod portion 64 is provided withflats 11 cooperating with corresponding flats in the screw shaftwhereby, when the screw shaft engages the flange 16 of the sleeve 48,and when the shoulder 18 on the screw shaft engages the shoulder 88 inthe spline nut 38, the nut 14 may be screwed home or released from theshank 68, as the case may be, without requiring a separate tool forholding the clutch member 52.

A spring 82, around the bearing sleeve 48 and behind the mesh rod 62,acts between the mesh rod flange 66 and a spring backing ring 83 ofangle section secured in position by split lock ring structure 84 heldin a groove in the screw shaft 46 to hold the mesh rod and the clutchmember 52 relative to the screw shaft in the given or initial positionsshown, and to allow the starter jaw member 52 to yield axially againstthe action of the spring 82 when the member 52 engages the engine jawelement 54.

In the latter connection, it is of particular note that the mesh rod 62does not slide axially in the jaw hub 58, as mesh rods generally do informer standard practice, but is normally a fixed part of the member 52'having a seal effected by the gasket 12, which is also normally fixed orpermanent at all times. It is of further note that this result isobtained, without resort to screw threads or other sharp edges tendingto start fracture of the jaw member, and without additional structure,or features, which deter free direct access from the exterior of thestarter to the holding means or nut 14 for the ready assembly andreplacement of the jaw 52.

In operation, when the shaft 36 is turned by the motor through theintermediary of the abovementioned gear or speed reducing means, the sungear 34 turns the planet gears 38, which, since they are carried by thebarrel 26 and are in mesh with the fixed orbital gear 32, react byturning the barrel 26 and, with the latter, the spline nut 38 throughthe intermediary of the disc clutch 48.

With the operating member or screw shaft 46 for the jaw member 52splined by the connection 58 to the jaw member 52, and the latterengaged by the combined oil seal and friction device 55, theabove-mentioned turning of the barrel 26 causes the screw shaft 46 toadvance to the left to first engage the member 52 to the engine element54. Continued rotation of the jaw member 52, when the shoulder 18engages the shoulder 88, drives the element 54 and the engine shaft 56to normally start the engine.

When the engine starts, the engine element 54 overrides the starter jawmember 52, and when the starter motor is deenergized, the member 52 iscammed back to the position shown, in a usual manner. If the engineshaft 56, for any reason, abnormally resists turning, or if the enginebackfires, the reaction is absorbed in the starter by the disc clutchpack 40.

Referring to Figure 3, the construction and operation are similar tothose above described, with substantially the only variations ofstructure germane to the invention residing in the rearrangement andform of a mesh rod 90, a screw shaft or operating member 92, a spring 99and associated parts. In this instance, the mesh rod 90 is hollow andlonger than the mesh rod 62, and encloses the spring 94, and has aflange 96 cooperating with the nut 14 to normally prevent completeseparation of the jaw member I04 from the operating member 92 and thestarter.

A sealing gasket I corresponding to the gasket I2, instead of being in agroove in the mesh rod, is in a groove I02 of a starter jaw I04, butmay, of course, be in a groove in the meshing rod or otherwiseconstituted to like effect.

The spring 94 acts similarly to the spring 02 between an internalshoulder 95 of the mesh rod 90 and means [06 carried by the screw shaft92. The means I06 comprises a spring backing member 91 corresponding tothe ring 83 of Figure 1, and a split lock ring structure 99corresponding to the ring 84 of Figure 1, and similarly held in a groovein the screw shaft 92.

As better shown in Figure 4, to avoid a sharp edge in the jaw I04itself, the groove I02 is provided with a well rounded fillet I08. Thegasket I00 shown, is of circular perimetral cross section of an areasuch that, when the nut 14 is turned home from its position of Figure 4to its position of Figure 3, the gasket is squashed over a broad area bythe clutch member I04 into broad area sealing engagement with a radialsurface of the mesh rod 90, at the right of the gasket as viewed in thedrawing, and with an annular surface of the rod under the gasket.

Although only two embodiments of the invention have been illustrated anddescribed, various changes in the form and relative arrangements of theparts, which will now appear to those skilled in the art, may be madewithout departing from the scope of the invention. Reference is,therefore, to be had to the appended claims for a definition of thelimits of the invention.

What is claimed is:

1. In an engine starter, the combination of a starter clutch memberadapted to engage an engine clutch portion, a screw shaft element, ameshing rod element, said elements telescopically fitting each other andhaving axially opposite lateral shoulders, a fluid seal between saidmember and the meshing rod, means fixing said member to said meshing rodand compressing said seal, and means including spring means operatingbetween the screw shaft and the meshing rod through said shoulders foradvancing the member into engagement with said portion.

2. In an engine starter, the combination of a starter clutch memberadapted to engage an engine clutch element, a spline nut, a screw shaftcooperating with said nut, a hollow meshing rod on which said member ismounted, and spring means in said rod responsive to axial movements ofsaid shaft to move said rod to engage said member to said element.

3. In an engine starter, the combination of a starter clutch memberadapted to engage an engine clutch element, a spline nut, a screw shaftcooperating with said nut, a meshing rod on which said member ismounted, and spring means behind said rod responsive to movement of said6 shaft to move said rod to engage said member to said element.

4. In an engine starter, the combination of a starter clutch memberadapted to engage an engine clutch element, an axially stationaryrotative driving nut, a screw shaft, a meshing rod, a nut or the likefor removably securing said member on said meshing rod, and meansincluding means for locking the screw shaft at opposite axial limits ofits travel relative to the driving nut and preventing turning of themeshing rod relative to the screw shaft and adapted to hold the meshingrod stationary for screwing said securing nut home at one of said limitsand releasing it at the other of said limits.

5. The combination of a casing, means including an axially stationaryrotatable nut and a hollow screw shaft cooperating with said nut in saidcasing for axial movement relative to said nut and rotative movementtherewith and having an inner flange, a clutch jaw member forcooperation with a clutch jaw element exteriorly of said casing, saidclutch member being connected for operation by said shaft for axial androtative movements with said shaft and axial movement relative thereto;and means for frictionally holding said clutch member to cause saidaxial movement thereof relative to said nut, spring means responsive tothe axial movement of said shaft to move said clutch member axiallytherewith into operative relation to the exterior clutch element, whichspring means yields for said axial relative movement and overriding ofsaid clutch member by said clutch element, said clutch jaw membernormally being permanently sealed against the passage of fluidtherethrough at all times including periods of said axial and rotativemovements, and means in said hollow screw shaft having a flange behindsaid inner flange holding said clutch member against separation fromsaid screw shaft and including means directly accessible from theexterior of said casing providing for said separation.

6. In an engine starter, the combination of a casing adapted formounting on the engine with one end of said casing in the engine crankcase, a starter clutch member mounted in an opening in said end exposedto oil in said crank case, a nut, means for frictionally holding andsealing said member relative to said casing, and means in said casingincluding a meshing rod on which said nut is mounted for removablyholding said member on said rod, an oil seal normally fixed in positionby said nut between said member and said rod, spring means, meansincluding a screw shaft for moving said member axially through theintermediary of said spring means into engagement with said engineclutch element and rotating said member to start the engine, and meansincluding said meshing rod and said screw shaft providing radial playbetween the rod and the shaft for rendering said member radially selfcentering relative to said element and prea lateral shoulder behind saidscrew shaft shoulder, spring backing means removably locked to the screwshaft therein, spring means between the mesh rod element and said springbacking .means through the intermediary of which the screw shaft movesthe starter jaw axially into engagement with an engine jaw, and meanscooperating between said shank and said wall locking the starter jaw tothe mesh rod element. RAYMOND H. FOSTER. CLINTON H. HAVILL.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 909,187 Illmer et a1. Jan. 12,1909 1,717,847 Litle June 18, 1929 1,990,015 Allen Feb. 5, 1935 102,316,121 Nardone Apr. 6, 1943 2,374,990 Gilbert May 1, 1945

